LONDON - OSU Extension is working with the USDA and Centers for Disease Control on strategies county fairs can take to minimize the spread of swine influenza.

More than 300 cases of flu in people contracted from swine mostly at county fairs were reported this year in the U.S., OSU Extension veterinarian Andy Bowman said. He spoke Thursday at the Farm Science Review in London.

The bulk of those nationwide cases were in Ohio (106) and Indiana. Just 12 to 13 human cases were reported across the U.S. last year, he said.

"We're discussing things like having pigs vaccinated two months before they come to a fair, shortening how long the pigs are there, making all shows terminal so the pigs can't go back into the herd and cause other infections and limiting the public's access to the barns," Bowman said. "Increasing signage at barns to warn people (about the potential of contracting flu) is another possibility."

Before this year's Mercer County Fair opened, two portable hand-washing stations were added to the hog barns and signage was erected telling people to wash their hands and not eat in the hog barns. All livestock barns already had hand sanitizers at the exits, fair board president Jeff Selhorst said.

"We're going to continue to be proactive," Selhorst said. "If a hog looks sick, we'll have the fair vet look at it."

The Auglaize County Fair had ended before the large number of swine influenza cases hit the media.

Fred Piehl, Auglaize County Fair manager, said the fair already had portable hand-washing stations, hand sanitizers and signage warning about hand washing and not eating in the barns. The fair will likely add more signs next year, he said.

No cases of swine influenza were reported at either local fair this year.

Since 2009, OSU Extension's Animal Influenza Ecology and Epidemiology Research Program has randomly tested 20 pigs per fair at an increasing number of fairs each year, Bowman said.

In 2009, pigs at 15 fairs were tested; this year, tests were done at 40 fairs.

The virus can be passed from pig to pig, pig to people and people to pig. A few cases of human-to-human infection also were found this year, Bowman said. Most of the human illnesses were mild; severe cases were in people with compromised immune systems.

The illnesses were caused by H3N2 and H1N1 flu strains.

"Flu in pigs is quite common and circulates constantly," Bowman said.

Officials speculate this year's outbreak was more severe because the virus changed. It is also easy to overlook sick animals because many times infected hogs do not show any symptoms, Bowman said.

"The concern is you have a barn full of pigs that don't look ill, and people visit the barns and it gets spread," he said.

Bowman said the vast majority of people who became ill this year were the swine exhibitors and/or their parents, but people can become ill from indirect contact as well. People cannot become sick by eating the meat of an infected animal.

Precautions exhibitors can take to minimize contracting flu from hogs include minimizing contact with the animals, vigilant hand washing and not sleeping in the barn with the animals. Exhibitors also should closely watch their hogs coming back from fairs for signs of infection before putting them back into the herd. Bowman pointed out that the way hogs are housed at fairs is contrary to the strict biosecurity standards the hog industry follows.

"When you bring pigs from multiple locations and house them all together for a week, things (illness) get mixed around," he said. "Swine producers would never do that."